角度 7 中的虚拟滚动、拖放

Question

I searched the internet for these new features of angular 7, but didn't fully understand it.

I went through drag and drop and virtual scrolling

Could someone please shed some light on these?

Answer 1

now consider a case where you are to display huge chunk of data, now either you will do pagination which will include an api call per page (if data changes frequently) or if you load everything at once which will slow down or kill UI process.

Virtual Scroll is about loading huge chunk of data in DOM without hampering the performance.

it's key features are:

1. data is displayed as per size of viewport ie if you container div is 500 px it will show around 10-15 rows at a time.
2. Ad you scroll these rows are changed but number of elements in the DOM will remain consistent.
3. This is handy when you have to show huge chunk of data without implementing pagination.

Thus it improves the UI performance. I implemented Virtual list displaying multiple column and array length was 1 million which is a huge amount of data to display at a time. Virtual list is implemented over virtual scroll and it supports multiple columns. check out detailed explanation and code here: https://www.codeproject.com/Articles/5260356/Virtual-List-in-Angular please have a look in the image: